Heretofore, crystalline polyolefins such as polyethylene and polypropylene when utilized as the thermoplastic component in thermoplastic vulcanizates have an upper continuous use temperature below 130.degree. C. due to the relatively low melting point of the crystalline thermoplastic phase (e.g. commercially available polypropylene has a melting temperature of 165.degree. C.). Accordingly, these hydrocarbon based compositions have limited use in under the hood applications of a vehicle where high temperatures are encountered and where low hydrocarbon oil swell is desirable. Blends of polar thermoplastics and polar rubbers in uncrosslinked form tend to have undesirable high compression set and poor mechanical strength. Conventional curatives for the polar rubbers generally have undesirable effects on a thermoplastic vulcanizate formed from a polyester and an acrylate rubber, such as degrading the thermoplastic or the release of undesirable volatile components during the curing process.